Polyhalo carboxylic acids



Sttes atent 3,056,773 Patented Oct. 2, 1962 3,056,773 POLYHALO CARBOXYLIC ACIDS Louis A. Joo, Crystal Lake, Waiter E. Kramer, Niles, and Theodore H. Szawlowski, Wonder Lake, 111., assignors it; Ellie Pure Oil Company, Chicago, [1]., a corporation o No Drawing. Filed Aug. 18, 1960, Ser. No. 50,334 18 Claims. (Cl. 260-128) This invention relates to halogenated, polynuclear, alkaryl carboxylic acids and more particularly to a new class of highly halogenated, complex, polynuclear, aromatic carboxylic acids prepared from solvent extracts obtained in the solvent extraction of mineral lubricating oils. More specifically, the invention is based on the discovery that the monoor polycarboxylic acids, described in co-pending application Serial No. 819,932, filed June 12, 1959, by Thomas W. Martinek, though known to contain double bonds, when halogenated produce a product having about 2 to 3 or more times as much halogen than that which would be predicted.

It becomes then a primary object of this invention to provide a new class of halogenated, polybasic, polynuclear, aromatic acids derived from the polybasic, polynuclear, aromatic acids disclosed in co-pending application Serial No. 819,932.

Another object of this invention is to provide highly halogenated, polybasic, polynuclear, aromatic acids of the general formula:

R-(COOHM ly wherein R is the residue or reactable portion of solvent extracts and is composed of compounds characterized by complex, polynuclear, aryl and alkaryl, and/or heterocyclic nuclei, a represents the number of carboxyl groups attached thereto, a having a value of at least 1 and preferably 2-5, X is a halogen (i.e., chlorine, bromine, iodine, fluorine, or mixtures thereof), and y is the number of halogen atoms attached to the residual group, y having a value of about 1 to 5.

These and other objects of this invention will be de scribed or become apparent as the specification proceeds. The starting materials for the instant invention are prepared from petroleum fractions, particularly solvent extracts rich in complex, polynuclear, aromatic compounds in accordance with said co-pending application Serial No. 819,932. The petroleum fractions rich in the above-defined complex hydrocarbons are aromatic-rich fractions obtained as by-products from the solvent refining of mineral oils.

For example, a preferred source of the above-defined complex hydrocarbons comprises the extracts obtained in solvent refining mineral oils, particularly lubricating oil fractions. These extracts, hereinafter referred to as solvent extracts, are obtained as the extract or solvent phase when lubricating oils are refined by treatment with a selective solvent having an affinity for aromatic and sulfur compounds. The complex hydrocarbons removed by this refining treatment often contain appreciable amounts of combined sulfur, nitrogen and oxygen. These complex hydrocarbons contain a predominance of polynuclear rings of aromatic structure, and of condensed configurations having or containing hydrocarbon substituent groups attached thereto as side chains. These starting materials are of a generally viscous nature, have low viscosity indices, low resistance to oxidation, and are considered to be deleterious in lubricating oils. Heretofore, these aromatic extracts have been regarded as waste products, and because they are exceedingly complicated mixtures of complex compounds, including various su1fur-, oxygen-, and nitrogen-containing compounds,

they have not been used successfully in preparing petrochemicals or as sources of hydrocarbon reactants or starting materials.

The previous art shows unsuccessful attempts at their utilization, but the above-defined, concentrated, complex aromatic hydrocarbons from solvent extracts obtained in lubricating oil manufacture can be successfully utilized to prepare mixed polyfunctional compounds of aromatic nature having many uses. More particularly, these aromatic oil fractions, containing from about 50% by weight to about by weight of the above-defined polynuclear, complex, substituted aromatic compounds, can be reacted with alkali metals in the presence of certain solvents to form complexes with the alkali metal, and these complexes can be further reacted with carbon dioxide to form alkali metal salts of mixed organic acids. By acidification or acid hydrolysis, the aforementioned salts can be transformed into free dibasic acids.

The starting materials used are adequately described as those aromatic materials separated from mineral lubricating oils and their fractions (i.e., those aromatics obtained in the manufacture and refining of neutral oils and bright stocks during treatment with a selective solvent designed to extract the predominantly aromatic materials from the paraifinic materials). Solvent extracts resulting from the treatment of mineral lubricating oils for the purpose of separating non-aromatic hydrocarbons (the ratfinate and finished oil) from the aromatic hydrocarbons (the extract and waste product) may be used and are preferred as starting materials.

Since the general process of refining mineral lubricating oils in which solvent extracts are obtained is well known, it is only necessary for present purposes to describe a typical procedure for obtaining same and give some examples by way of illustration.

In a typical operation, desalted crude oil is first charged to a distillation unit where straight-run gasoline, two grades of naphtha, kerosine, and virgin distillate are taken off, leaving a reduced crude residue. The reduced crude is continuously charged to a vacuum distillation unit where three lubricating oil distillates are taken off as side streams, a light distillate is taken off as overhead, and a residum is withdrawn from the bottom of the tower. The residuum is charged to a propane-deasphalting unit wherein propane dissolves the desirable lubricating oil constituents and leaves the asphaltic materials. A typical vacuum residuum charge to the propane-deasphalting unit may have an API gravity of 12.9", viscosity SUS at 210 F. of 1249, flash 585 F., fire 650 F., OR. of 13.9 weight percent, and may be black in color. The deasphalted oil may have an API gravity of 21.5 to 21.8, viscosity SUS at 210 F. of -175, NPA color 6-7, flash 575 F., fire 650 F., and OR. of 1.7-2.0. The deasphalted oil and various lubricating oil distillates from the reduced crude are subjected to solvent extraction for the separation of non-aromatic from aro matic constituents prior to use. The refined oil or raffinate from the extraction processes is used per se, or as blending stock, for lubricating oils, and the solvent extract, predominating in complex aromatic constituents, is distinctively useful in accordance with this invention.

For example, a crude oil from an East Texas field, with an API gravity of 33.1, was topped to remove such light fractions as gasoline. naphtha, kerosine, and a light lubricating distillate. The vacuum residue was a reduced crude, having a viscosity of 1251 SUS at 210 F., 2.2 percent sulfur, and an API gravity of 12.6. After propane-deasphalting, the oil had a viscosity of 174 SUS at 210 F., and an API gravity of 21.7. This deasphalted oil was treated with phenol to produce a raffinate from which an aviation lubricating oil could be prepared. The oil extracted by phenol treatment, after removal of phe- 1101, is ready for use as the starting material in accordance with this invention.

Solvents other than phenol may be used to obtain the extraction product used in accordance With this invention,

41 these extracts increase with decrease in viscosity index of the rafiinate at a constant viscosity. For the production of 10015 V1 neutral oils, the viscosities of the extracts increase with increase in stated viscosities of the neutral for example, liquid sulfur dioxide, nitrobenzene, Chlorex, oils (raflinates). The pour points of extracts are high chlorophenol, trichloroethylene, cresylic acid, pyridine, and are affected by changes in the depth of extraction. furfural, or the Duo-Sol solution (comprising liquid pro- The sulfur contents are also affected by the depth of expane and cresol) may be used. When using phenol, it traction. The solvent extracts are characterized by conis possible to vary the characteristics of the extract and taining aromatic and heterocyclic compounds in the range rafiinate products considerably by adjustment of the of 75-98%, the remainder being principally saturates, or amount of water present. A raffinate of relatively low material behaving as saturates, together with a minor viscosity index can be obtained by using a Water solution proportion of up to about 7% of organic acids. The of phenol during the extraction, and a raffinate of high organic acids present are not susceptible to extraction by vicosity index can be obtained by using anhydrous phenol. the use of aqueous strong caustic because of the solu- Following are the physical characteristics of typical exbility of the alkali metal salts of the acids in the oil. tract products, from lubricating oil stocks derived from Little or no asphaltic material is present in solvent exvarious crude oils and other source hydrocarbon matetracts and they contain essentially no materials volatile rials, which may be used in accordance with this invenat room temperature.

tion. The complexity of the types of compounds present, as

TABLE I Sources and Physical Characteristics of Solvent Extracts Ext API Sp. gr. Vis./ Vis./ Vis./ F. F. Iodine Percent Percent No Crude source Solvent grav. atr10 100 F 130 F 210 F. V.I. Pour flash fire narfnbtfir C sulfur ijs 1.... East Tex 11.1 2 d 15. 4 12. 6 14. 6 15.4 13.7 8. 6 do 10. 5 9 Santa Fe Springs 10. 2 10 Texas 13.0 11-" Pennsylvania. 12. 2 do Nitro-benzeno 10. O Mid-Cont.-- Propane-cresol 13.6 8. 9 14. 9 13. 5 11.1 13. 7 7. 7 7.3

The solvent extracts from lubricating oils used as starting materials for this invention have the following general properties and characteristics:

The specific gravities of the extracts in general increase with increase in the viscosity of the rafiinate at a constant viscosity index. Stated otherwise, the specific gravities of based on these analyses, is illustrated by the following table:

TABLE III Estimated Chemical Composition of Solvent Extracts Nos. 19 and 21 0 Table 1 Approx. percent Type of compound: in the extract Saturated hydrocarbons 12.5 Mononuclear aromatics: Substituted benzenes 25.0 Dinuclear aromatics: Substituted naphthalenes 30.0

Trinuclear aromatics:

Substituted phenanthrenes 10.0 Substituted anthracenes 5.0 Tetranuclear aromatics:

Substituted chrysenes 00.5 Substituted benzphenanthrenes 0.2 Substituted pyrenes 0.2 Pentanuclear aromatics: Perylene 0.01

Sulfur compounds, oxygen compounds, etc; 16.5

1 Mainly heterocyclic Compounds. The average mol. weight of Extracts 19 and '21 is 340, and that of Extract 20 is 590 Any portion of the reactive aromatic constituents in solvent extracts may be isolated therefrom, or from other sources, to be used as starting materials for the reaction with a halogen in accordance with this invention. For example, solvent extracts may be distilled and selected fractions thereof used as the starting materials. The content of reactive, complex, polynuclear, aromatic compounds and heterocyclics present in solvent extracts, as illustrating the preferred source material, may vary depending on the type of solvent, the extraction process applied, and the mineral oil treated, although the general types of compounds present in the extract are not so varied. Extracts containing from about 30% to 90% of polynuclear aromatics and heterocyclics of aromatic nature represent a preferred type of starting material.

EXAMPLE I A 20-g. portion of polybasic, polynuclear, aromatic acids, which had been prepared by reacting an aromaticrich extract oil (No. 23 of Table I) with metallic sodium in the presence of an active solvent, then reacting the metal-organic adduct with carbon dioxide, and finally acidifying the water-soluble products thereof to obtain the free acids, was dissolved in 4-00 ml. of glacial acetic acid and 20 ml. of concentrated hydrochloric acid and 7.5 ml. of 30% hydrogen peroxide were added. The reaction mixture was boiled occasionally during a period of two hours, after which it was boiled vigorously for 20 minutes to drive off any oxygen and chlorine liberated by the reactions which had occurred. The resulting product was treated with 150 ml. of ether, and with several ZOO-ml. portions of water, to wash out the excess hydrochloric and acetic acids and effect an ether extraction of the chlorinated product, after which it was stripped free of the ether to recover the highly halogenated acid mixture of this invention.

The acids used in this experiment had an initial bromine number of 19, indicating that 0.119 gram-mole of halogen were reactive with the olefinic double bonds in 100 g. of the acid. The product obtained in the experiment contained 19% wt. chlorine, indicating that 0.33 gram-mole of chlorine had been incorporated per 100 g. of acid. Thus, it is apparent that the amount of chlorine which had been incorporated in the acid mixture was 2.75 times the amount which would have been predicted based only on the expected addition (bromine minimum) to the olefinic double bonds. At the same time, the sulfur content was reduced from 1.98% wt. to 1.6% wt., part of this reduction being merely apparent and resulting from the increase in molecular weight caused by the incorporation of chlorine. But part of the reduction was real and resulted from some mechanism which remains unexplained at this time. The acid number of the material was diminished by only the amount expected from the increase in molecular weight brought about by the incorporated chlorine. Consequently, the reactivity of the acids in preparing resins was not impaired.

EXAMPLE II A 20-g. portion of polybasic, polynuclear, aromatic acids, which had been prepared by reacting an arcmatic-rich extract oil (No. 23 of Table I) with metallic sodium in the presence of an active solvent, then reacting the metal-organic adduct with carbon dioxide, and finally acidifying the watersoluble products thereof to obtain the free acids, is dissolved in 400 ml. of glacial acetic acid and 20 ml. of concentrated hydrobromic acid and 7.5 ml. of 30% hydrogen peroxide are added. The reaction mixture is boiled occasionally during a period of two hours, after which it is boiled vigorously for 20 minutes to drive off any oxygen and bromine liberated by the reactions which occur. The resulting product is extracted with 15 0 ml. of ether, after which it is stripped free of the ether and acetic acid to recover the highly halogenated acid mixture of this invention.

The acids for such an experiment have an initial bromine number of about 19, indicating that 0.119 gram-mole of halogen would be reactive with the olefinic double bonds in g. of the acid. The product from such an experiment contains about 34.5% by Weight of bromine, indicating that 0.33 gram-mole of bromine is incorporated per 100 g. of acid. Thus, it is apparent that the amount of bromine which is incorporated in the acid mixture is 2.75 times the amount which would have been predicted, based only on the expected addition bromine number to the olefinic double bonds. At the same time, the sulfur content is reduced from 1.98% wt. to 1.3% wt., part of this reduction being merely apparent and resulting from the increase in molecular weight caused by the addition of bromine atoms. But part of the reduction is real and results from some mechanism which remains unexplained at this time. The acid number of the material is diminished by only the amount expected from the increase in molecular weight brought about by the bromine incorporated. Consequently, the reactivity of the acids for preparing resins is not impaired.

EXAMPLE III A 20-g. portion of polybasic, polynuclear, aromatic acids, which had been prepared by reacting an aromaticrich extract oil (No. 22 of Table l) with metallic sodium in the presence of an active solvent, then reacting the metal-organic adduct with carbon dioxide, and finally acidifying the water-soluble products thereof to obtain the free acids, is dissolved in 400 ml. of glacial acetic acid and 20 ml. of concentrated hydroiodic acid and 7.5 ml. of 30% hydrogen peroxide are added. The reaction mixture is boiled occasionally during a period of two hours, after which it is boiled vigorously for 20 minutes to drive off any oxygen and iodine liberated by the reactions which occur. The resulting product is extracted with ml. of ether, after which it is stripped free of the ether and acetic acid to recover the highly halogenated acid mixture of this invention.

The acids for this experiment have an initial bromine number of about 19, indicating that 0.119 gram-mole of halogen would be reactive with the olefinic double bonds in 100 g. of the acid. The product from such an experiment contains 45.0% by wt. iodine, indicating that 0.33 gram-mole of iodine is incorporated per 10-0 g. of acid. Thus, it is apparent that the amount of iodine which is incorporated in the acid mixture is 2.75 times the amount which would have been predicted based only on the expected addition (bromine number) to the olefinic double bonds. At the same time, the sulfur content is reduced from 1.98% wt. to 1.1% wt, part of this reduction being merely apparent and resulting from the increase in molecular weight caused by the addition of iodine atoms. But part of the reduction is real and results from some mechanism which remains unexplained at this time. The acid number of the material is diminished by only the amount expected from the increase in molecular weight brought about by the iodine incorporated. Consequently, the reactivity of the acids for preparing resins is not impaired.

Various known methods of introducing halogen atoms into organic compounds may be used to prepare the products of this invention. Since the complex organic compounds used as starting materials apparently have several functional sites which are vulnerable to attachment of a halogen atom, direct halogenation may be used. However, in using this method, there is the inconvenience of handling free halogen. The reaction may be conducted slowly at room temperature, or may be accelerated by the use of heat and light. Direct halogenation proceeds rapidly in the vapor phase. In general, substitution occurs most readily with tertiary hydrogens in the complex molecule and least at primary positions. At elevated temperatures, these types of substitution approach equality, as in the halogenation of alkanes. The alkene portions of the molecule produce alkyl-type monohalide linkages when directly halogenated at elevated temperatures. Side chains attached to aromatic nuclei can be directly halogenated in sunlight and in the absence of a catalyst. Nuclear halogenation can be accomplished by use of bromine, iodine or chlorine at temperatures of from 300 to 500 C. Direct bromination or chlorination may be conducted using red phosphorus or phosphorus halides as carriers. Peroxide-catalyzed chlorination with sulfuryl chloride is another technique that may be used. The reaction of hydrogen halides with unsaturates constitutes a convenient method of preparing the derivatives of this invention. Such reactions with hydrogen bromide or hydrogen iodide take place at room temperatures to 100 C., but the addition of hydrogen chloride requires temperatures from 75 to 200 C. In these reactions, such solvents as benzene, pentane and ether may be used. The invention is not to be limited to any particular method of halogenation.

In utilizing solvent extracts to prepare haloacids in accordance with this invention, the amount of reactable polynuclear, complex aromatic materials present in the extract is of no particular consequence except as it relates to the economic feasibility of the process. Many extracts contain less than 50% by weight of reactalrie, polynuclear, complex aromatic compounds and these starting materials may be used in the instant process. Some extracts contain from to of reactable polynuclear aromatics whereas well over of the extract consists of polynuclear aromatic compounds. Solvent extracts containing less than 35% by weight of reactable polynuclear aromatic compounds may still prove to be economically feasible.

In order to further illustrate the complete process the following example is given.

EXAMPLE IV One hundred and fifty-four grams of the bromoacid prepared in Example II is heated with 100 grams of RF for two hours, with stirring. After cooling, the acid is extracted from the mixture with diethyl ether. The ether is evaporated to yield the free acid. The product after reaction weighs about 113 grams. Analysis for fluorine reveals 11.5% fluorine, or 0.33 mole of fluorine present per 100 grams of acid. The chloro or iodoacids also can be used in this reaction to prepare the fluoroacids. Similar results are obtained with Extracts Nos. l-8 of Table I.

The polyhalopolynuclear polybasic acids of this invention are a new class of acids characterized by the mixed polynuclear aryl and/or alkaryl nuclei derived from solvent extracts. Although the products find utility in themselves as organic acids, they contain a high concentration of halogen and as such are adapted to resin preparation, particularly in the preparation of resins having appreciable hardness and fire-retarding properties. The polyhaloacids of this invention may be esterified, polymerized, and transformed into amides to form resins and plastic materials for use in coatings, as plasticizers and organoacids for these purposes is well known in the art, there is no necessity to describe in detail the methods of preparation or reactions in which the polyhaloacids of this invention may be employed.

Because of the complex nature of the acid starting materials for the halogenation reactions, and the distinguishing features of the aromatic starting materials as shown in Tables I and II, a feature of the invention is the discovery that the amount of halogen that can be introduced into the polynuclear acids is greater than the amount one would predict from the bromine number of the starting materials. It has been found that the average bromine number of the acids is between about 16 to 22. Theoretically, this would mean that about 13.8 to 18.0 wt. percent of bromine could be introduced if the bromine adds to the olefinic double bonds. We have found, however, that the bromine content is about 2.75 times these amounts. Since the starting material is a mixture of complex, polynuclear, aryl and/ or alkaryl compounds, and there is no loss due to decarboxylation or dealkylation during the reaction, those products which apparently have only one halogen atom per molecule are still defined as polyhalo because they constitute a mixture with more than one type of product. The R group is defined as a residue of a solvent extract having at least one active site. This means that there is at least one and preferably more than one, position in the molecule or molecules of the acids which will accept a halogen atom. Accordingly, although some of the individual acids in the final product mixture may contain only one halogen atom, the mixture may still be considered polyhalogenated because other individual acid molecules contain more than one halogen atom. Y may have a value of 2 to 5 for the average polyhalogenated compositions.

In addition to the general physical and chemical properties of the solvent extracts given in Table II, these starting materials may be further characterized by the fact that their average molecular weight is about 320 to 600, the boiling point (initial) is between 300 to 1000 F., the end boiling point is between 400 to 1200 F., and they may exhibit pour points as high as 100 F. Chemically, the extracts may contain 2.0 to 4.5% Wt. of sulfur, exhibit a H/C wt. ratio of 0.116 to 0.136, a H/C atom ratio of 1.383 to 1.622, a H/C atom ratio, based only on the aromatic portion, of 1.289 to 1.500, and the nearest empirical formula is (3 1-1 to (3 1-1 The extracts may contain from about 15% to 50% by weight of sulfur compounds, and 30% to by weight of aromatic and thio compounds. Many of these characteristics, particularly the chemical characteristics, carry over into the polynuclear polyhaloacids of this invention.

The terms residue of solvent extracts and reactable portion of solvent extracts have been used synonymously herein to mean the complex organic portion of the extracts resulting from metalation, carbonation, and acidification, in accordance with the process of application Serial Number 819,932, exclusive of carboxyl groups.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Halo, polynuclear carboxylic acids prepared by reacting solvent extracts, obtained in the solvent refining of mineral lubricating oils with a solvent selective for aromatic compounds, with an alkali metal to form the alkali metal adduct, carbonating said adduct to form the alkali metal salt of said acids, acidizing the resulting salt to form the free carboxylic acids and halogenating said free acids.

2. A composition of matter in accordance with claim 1 in which said acids are characterized by complex polynuclear, aryl, alkaryl radicals having an average molecular weight of above about 300 with about 1.7 to 3.5 aromatic rings per mean aromatic molecule.

3. A composition of matter in accordance with claim 1 in which said carboxylic acids contain 1 to 5 carboxyl groups and 1 to 5 halogen atoms per molecule.

4. A composition of matter in accordance with claim 1 in which the halogen is chlorine.

5. A composition of matter in accordance with claim 1 in which the halogen is bromine.

6. A composition of matter in accordance with claim 1 in which the halogen is iodine.

7. A composition of matter in accordance with claim 1 in which the halogen is fluorine.

8. A halo, polynuclear mixed mono-, di-, and polycarboxylic acids prepared by reacting solvent extracts, obtained in the solvent refining of mineral lubricating oils with a solvent selective for aromatic compounds, with an alkali metal to form the alkali metal adduct, carbonating said adduct to form the alkali metal salts of said acids, acidifying the resulting salts to form the free carboxylic acids and halogenating said free acids.

9. A composition of matter in accordance with claim 8 in which said acids are characterized by complex, polynuclear, aryl, alkaryl radicals having an average molecular weight of above about 300 with about 1.7 to 3.5 aromatic rings per mean aromatic molecule.

10. A composition of matter in accordance with claim 8 in which said carboxylic acids contain 1 to 5 carboxyl groups and 1 to 5 halogen atoms per molecule.

11. A composition of matter in accordance with claim 8 in which the halogen is chlorine.

12. A composition of matter in accordance with claim 8 in which said halogen is bromine.

13. A composition of matter in accordance with claim 8 in which said halogen is iodine.

14. A composition of matter in accordance with claim 8 in which said halogen is fluorine.

15. Polyhalo, polynuclear mixed mono-, di, and polycarboxylic acids characterized by complex, polynuclear, aryl, alkylaryl and heterocyclic radicals having an average molecular weight of about 320 to 600, a sulfur content of between about 2.0 to 4.5 wt. percent, about 1.7 to 3.5 aromatic rings per mean aromatic molecule, and containing 1 to 5 carboxyl groups and 2 to 5 halogen atoms per molecule, prepared by reacting solvent extracts, obtained in the solvent refining of mineral lubricating oils with a solvent selective for aromatic compounds with an alkali metal to form the alkali metal adduct, carbonating said adduct to form the alkali metal salt of the corresponding carboxylic acid, acidifying said salt to form the free acids and halogenating said free acids.

16. 'Polychloro, polynuclear mixed mono-, di-, and polycarboxylic acids, prepared by reacting phenol extract from the phenol solvent extraction of mineral lubricating oils with metallic sodium in the presence of a reaction solvent to form the sodium adduct of the complex polynuclear alkyl aromatic and heterocyclic compounds, reacting said adduct with carbon dioxide to form the sodium salts of the corresponding carboxylic acids, acidifying said salts to form the free acids, and reacting said free acids with concentrated hydrochloric acid in glacial acetic acid in the presence of hydrogen peroxide to form said polychlorinated product.

17. Polybromo, polynuclear mixed mono-, di-, and polycarboxylic acids, prepared by reacting phenol extract from the phenol solvent extraction of mineral lubricating oils with metallic sodium in the presence of a reaction solvent to form the sodium adduct of the complex polynuclear alkyl aromatic and heterocyclic compounds, reacting said adduct with carbon dioxide to form the sodium salts of the corresponding carboxylic acids, acidifying said salts to form the free acids and reacting said free acids with concentrated hydrobromic acid in glacial acetic acid in the presence of hydrogen peroxide to form said polybrominated product.

18. Polyiodo polynuclear mixed mono-, di-, and polycarboxylic acids, prepared by reacting phenol extract from the phenol extraction of mineral lubricating oils with metallic sodium to form the sodium adduct of the complex polynuclear alkyl aromatic and heterocyclic compounds, reacting said adduct with carbon dioxide to form the sodium salts of the corresponding carboxylic acids, acidifying said salts to form the free acids and reacting said free acids with concentrated hydriodic acid in glacial acetic acid in the presence of hydrogen peroxide to form said polyiodated product.

No references cited. 

1. HALO, POLYNUCLEAR CARBOXYLIC ACIDS PREPARED BY REACTING SOLVENT EXTRACTS, OBTAINED IN SOLVENT REFINING OF MINERAL LUBRICATING OILS WITH A SOLVENT SELECTIVE FOR AROMATIC COMPOUNDS, WITH AN ALKALI METAL TO FORM THE ALKALI METAL ADDUCT, CARBONATING SAID ADDUCT TO FORM THE ALKALI METAL SALT OF SAID ACIDS, ACIDIZING THE RESULTING SALT TO FORM THE FREE CARBOXYLIC ACIDS AND HALOGENATING SAID FREE ACIDS. 